Hemiplegic (unilateral) cerebral palsy in northern Stockholm: clinical assessment, brain imaging, EEG, epilepsy and aetiologic background factors.

BACKGROUND: The purpose of this study was to describe clinical presentation, epilepsy, EEG, extent and site of the underlying cerebral lesion with special reference towards aetiologic background factors in a population-based group of children with hemiplegic cerebral palsy. METHODS: Forty-seven children of school- age, fulfilling the SPCE (Surveillance of Cerebral palsy in Europe)-criteria of hemiplegic cerebral palsy, identified via the Swedish cerebral palsy register, were invited and asked to participate in the study. RESULTS: Fifteen boys and six girls participated. Of the sixteen children born at term, five had no risk factors for cerebral palsy. Two out of five preterm children presented additional risk factors. Debut of motor impairment was observed in the first year of life in sixteen children. Age at diagnosis varied from 2 months to 6 years. Epilepsy was common and associated with grey- and white matter injury. CONCLUSIONS: Recognizing the importance of risk factors for cerebral palsy, any child with these risk factors should be offered a check-up by a paediatrician or a paediatric neurologist. Thereby reducing diagnostic delay. Epilepsy is common in hemiplegic cerebral palsy and associated with grey- and white matter injury in this cohort.

Quantification of Trapezius Muscle Innervation During Neck Dissections: Cervical Plexus Versus the Spinal Accessory Nerve.

OBJECTIVES: Despite increasing use of selective, nerve-sparing surgical techniques during neck dissections, the reported rate of postoperative paralysis of the trapezius muscle is still high. The aim of the study is to measure and compare motor inflow to the trapezius muscle, in order to better understand the peripheral neuroanatomy. METHODS: Intraoperative nerve monitoring (electroneurography) in patients undergoing routine neck dissection (n=18). The innervation of the 3 functional parts of the trapezius muscle was mapped and quantified through compound muscle action potentials. RESULTS: In 18/18 (100%) of the patients, the spinal accessory nerve (SAN) innervated all parts of the trapezius muscle. In 7/18 (39%) of the patients, an active motor branch from the cervical plexus was detected, equally distributed to all functional parts of the trapezius muscle, at levels comparable to the SAN. CONCLUSIONS: Compared to the SAN, branches from cervical plexus provide a significant amount of neural input to all parts of the trapezius muscle. Intraoperative nerve monitoring can be used in routine neck dissections to detect these branches, which may be important following surgical injury to the SAN.

New animal model for assessment of functional laryngeal motor innervation.

OBJECTIVES: The functional motor innervation of the larynx is not fully understood because of the complexity of the peripheral neuroanatomy. Since the late 19th century, there has been controversy regarding the role of the superior laryngeal nerve, which may have wider motor projections than are currently acknowledged. The aim of this study was to develop a large animal model to characterize and quantify the functional motor input to the intrinsic laryngeal muscles. METHODS: We performed invasive electrophysiology (evoked electromyography) in normal pigs. RESULTS: The thyroarytenoid, lateral cricoarytenoid, and posterior cricoarytenoid muscles receive dual innervation from both the superior and recurrent laryngeal nerves, whereas the cricothyroid muscle is innervated only by the superior laryngeal nerve. CONCLUSIONS: The dual innervation pattern from both laryngeal nerves supports the concept of a laryngeal nerve plexus. The motor input through the external branch of the superior laryngeal nerve was surprisingly high. The animal model presented here may be used in future investigations of laryngeal reinnervation following nerve injury.

FGF1 containing biodegradable device with peripheral nerve grafts induces corticospinal tract regeneration and motor evoked potentials after spinal cord resection.

PURPOSE: Repairing the spinal cord with peripheral nerve grafts (PNG) and adjuvant acidic fibroblast growth factor (FGF1) has previously resulted in partial functional recovery. To aid microsurgical placement of PNGs, a graft holder device was previously developed by our group. In hope for a translational development we now investigate a new biodegradable graft holder device containing PNGs with or without FGF1. METHODS: Rats were subjected to a T11 spinal cord resection with subsequent repair using twelve white-to-grey matter oriented PNGs prepositioned in a biodegradable device with or without slow release of FGF1. Animals were evaluated with BBB-score, electrophysiology and immunohistochemistry including anterograde BDA tracing. RESULTS: Motor evoked potentials (MEP) in the lower limb reappeared at 20 weeks after grafting. MEP responses were further improved in the group treated with adjuvant FGF1. Reappearance of MEPs was paralleled by NF-positive fibers and anterogradely traced corticospinal fibers distal to the injury. BBB-scores improved in repaired animals. CONCLUSIONS: The results continue to support that the combination of PNGs and FGF1 may be a regeneration strategy to reinnervate the caudal spinal cord. The new device induced robust MEPs augmented by FGF1, and may be considered for translational research.

Selectivity in the reinnervation of the lateral gastrocnemius muscle after nerve repair with ethyl cyanoacrylate in the rat.

There is a need for complementary surgical techniques that enable rapid and reliable primary repair of transected nerves. Previous studies after peripheral nerve transection and repair with synthetic adhesives have demonstrated regeneration to an extent comparable to that of conventional techniques. The aim of this study was to compare two different repair techniques on the selectivity of muscle reinnervation after repair and completed regeneration. We used the cholera toxin B technique of retrograde axonal tracing to evaluate the morphology, the number, and the three-dimensional location of α-motoneurons innervating the lateral gastrocnemius muscle and compared the results after repair with either ethyl cyanoacrylate (ECA) or epineural sutures of the transected parent sciatic nerve. In addition, we recorded the wet weight of the muscle. Six months after transection and repair of the sciatic nerve, the redistribution of the motoneuron pool was markedly disorganized, the motoneurons had apparently increased in number, and they were scattered throughout a larger volume of the spinal cord gray matter with a decrease in the synaptic coverage compared to controls. A reduction in muscle weight was observed as well. No difference in morphometric variables or muscle weight between the two repair methods could be detected. We conclude that the selectivity of motor reinnervation following sciatic nerve transection and subsequent repair with ECA is comparable to that following conventional micro suturing.

Desensitizing the posterior interosseous nerve alters wrist proprioceptive reflexes.

PURPOSE: The presence of wrist proprioceptive reflexes after stimulation of the dorsal scapholunate interosseous ligament has previously been described. Because this ligament is primarily innervated by the posterior interosseous nerve (PIN) we hypothesized altered ligamento-muscular reflex patterns following desensitization of the PIN. METHODS: Eight volunteers (3 women, 5 men; mean age, 26 y; range 21-28 y) participated in the study. In the first study on wrist proprioceptive reflexes (study 1), the scapholunate interosseous ligament was stimulated through a fine-wire electrode with 4 1-ms bipolar pulses at 200 Hz, 30 times consecutively, while EMG activity was recorded from the extensor carpi radialis brevis, extensor carpi ulnaris, flexor carpi radialis, and flexor carpi ulnaris, with the wrist in extension, flexion, radial deviation, and ulnar deviation. After completion of study 1, the PIN was anesthetized in the radial aspect of the fourth extensor compartment using 2-mL lidocaine (10 mg/mL) infiltration anesthesia. Ten minutes after desensitization, the experiment was repeated as in study 1. The average EMG results from the 30 consecutive stimulations were rectified and analyzed using Student's t-test. Statistically significant changes in EMG amplitude were plotted along time lines so that the results of study 1 and 2 could be compared. RESULTS: Dramatic alterations in reflex patterns were observed in wrist flexion, radial deviation, and ulnar deviation following desensitization of the PIN, with an average of 72% reduction in excitatory reactions. In ulnar deviation, the inhibitory reactions of the extensor carpi ulnaris were entirely eliminated. In wrist extension, no differences in the reflex patterns were observed. CONCLUSIONS: Wrist proprioception through the scapholunate ligament in flexion, radial deviation, and ulnar deviation depends on an intact PIN function. The unchanged reflex patterns in wrist extension suggest an alternate proprioceptive pathway for this position. Routine excision of the PIN during wrist surgical procedures should be avoided, as it alters the proprioceptive function of the wrist. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Hand function in relation to brain lesions and corticomotor-projection pattern in children with unilateral cerebral palsy.

AIM: To investigate relationships between hand function, brain lesions, and corticomotor projections in children with unilateral cerebral palsy (CP). METHOD: The study included 17 children (nine males, eight females; mean age 11.4 [SD 2.4] range 7-16 y), with unilateral CP at Gross Motor Function Classification System level I and Manual Ability Classification System level I or II. Hand function was assessed with the Box and Blocks test and Assisting Hand Assessment (AHA). Conventional structural magnetic resonance images were assessed visually for type, location, and extent of brain lesions. Single-pulse transcranial magnetic stimulation (TMS) provided information on organization of corticomotor projections. RESULTS: The most favourable hand function was seen in children who had white-matter damage of immaturity with mild white-matter loss and contralateral motor projections. Children with ipsilateral projections had the most impaired function. Nevertheless, in this subgroup a range of ability was seen (AHA 29-59%). Motor-projection patterns appeared to be influenced by lesion extent and location, but not by lesion type. INTERPRETATION: Combining information from structural magnetic resonance images and TMS can improve prediction of hand function. A wide variation in hand function was seen within all motor-projection patterns. Although the most impaired hand function was seen in the ipsilateral motor-projection group, some children in this group had fairly good ability. Such information is important for treatment planning.

Peripheral nerve grafts in a spinal cord prosthesis result in regeneration and motor evoked potentials following spinal cord resection.

PURPOSE: To evaluate whether a standardized nerve graft bridging of a spinal cord injury gap in a device with white to grey matter projections allows regeneration and electrophysiological contact from supraspinal centers to the leg, since previous studies using nerve grafts in combination with acidic fibroblast growth factor have been difficult to microsurgically reproduce. METHODS: A moulded prosthesis containing twelve peripheral nerve grafts with estimated pre-set projections guiding white tracts to grey matter replaced a spinal cord resection gap at level T11 in adult rats. The animals were evaluated with electrophysiology, morphology, immunohistochemistry and functional scoring. RESULTS: At six months postoperatively the grafts were found to be positioned at the desired locations, motor evoked potentials were detected in 80% of the animals subjected to nerve graft bridging. Morphology and immunohistochemical analysis revealed numerous de novo axons in the grafts, which possibly reached into the spinal cord on the other side. CONCLUSION: Replacing the resected spinal cord with oblique peripheral nerve grafts results in spinal cord regeneration and positive motor evoked potential. Transplantation of nerve grafts organized in a prosthesis is re-producible, sustains desired projections and ensures transverse ends towards the spinal cord surface and may be useful in the future.

Diagnosis and prognosis of iatrogenic injury of the recurrent laryngeal nerve.

OBJECTIVES: Following perioperative injury to a macroscopically intact recurrent laryngeal nerve (RLN), there are two possible intraneural injury types: 1) axonal injury, including disruption of axons, and 2) conduction block, only affecting the Schwann cells and the nodes of Ranvier. In this study, it was hypothesized that the functional outcome after RLN injury may depend on the type of nerve injury. METHODS: Fifteen patients with acute postoperative unilateral RLN paralysis were prospectively studied. Electrophysiological examination (laryngeal electromyography) was used to differentiate between the two types of nerve injury. Vocal fold motions were monitored by repeated laryngoscopy during the study period (up to 6 months). Three of the patients with axonal injury were treated with the regeneration-promoting agent nimodipine. RESULTS: The patients with conduction block all recovered normal vocal fold motion, whereas patients with axonal injury within the nerve had a significantly worse outcome. The 3 patients who were treated with nimodipine all recovered normal or near-normal vocal fold mobility despite the more severe axonal injury. CONCLUSIONS: In contrast to previous reports, our results show that laryngeal electromyography is a reliable tool for diagnosing the type of injury within the injured RLN, making it possible to predict the functional outcome in these patients. On the basis of the results, a future randomized study on nimodipine treatment for RLN axonal injury is suggested.

Evidence of wrist proprioceptive reflexes elicited after stimulation of the scapholunate interosseous ligament.

PURPOSE: Recent publications on the sensory innervation of wrist ligaments have challenged our understanding of ligaments as mere passive restraints in wrist stability. Mechanoreceptors in ligaments have a role in signaling joint perturbations, in which the afferent information is believed to influence periarticular muscles. The scapholunate interosseous ligament is one of the most richly innervated ligaments in the wrist. The purpose of our study was to investigate the possible existence of a wrist proprioceptive reflex, by which afferent information elicited in the scapholunate interosseous ligament was hypothesized to influence the muscles moving the wrist joint. METHODS: Nine volunteers (4 women and 5 men; mean age, 26 years; range, 21-28 years) participated in this study. Using ultrasound guidance, a fine-wire electrode was inserted into the dorsal scapholunate interosseous ligament and stimulated with four 1-ms pulses at 200 Hz. Electromyographic activities in extensor carpi radialis brevis, extensor carpi ulnaris, flexor carpi radialis, and flexor carpi ulnaris muscles were recorded using surface electrodes with the wrist actively positioned in isometric extension, flexion, and radial and ulnar deviation. The average EMGs from 30 consecutive stimulations were rectified and analyzed using the Student's t-test to compare the prestimulus (t(1)) and poststimulus (t(2)) EMG activities. RESULTS: Statistically significant changes in poststimulus EMG activity (t(1)- t(2)) were observed at various time intervals. Within 20 ms, an excitation was seen in the flexor carpi radialis and flexor carpi ulnaris in extension, radial and ulnar deviation, and in extensor carpi radialis brevis in flexion. Co-contractions between agonist and antagonist muscles were observed, with peaks around 150 ms after stimulus. CONCLUSIONS: We present evidence of wrist ligamento-muscular reactions. The early-onset reactions may serve in a joint-protective manner, and later co-contractions indicate a supraspinal control of wrist neuromuscular stability. These findings contribute new information to the physiologic functions of the wrist joint, which may further our understanding of dynamic wrist stability and serve as a foundation for future studies on proprioceptive dysfunctions after wrist ligament injuries.

Bilateral vagotomy inhibits apnea and attenuates other physiological responses after blunt chest trauma.

BACKGROUND: Behind armor blunt trauma (BABT) is defined as the nonpenetrating injury resulting from a ballistic impact on body armor. Some of the kinetic energy is transferred to the body, causing internal injuries and, occasionally, death. The aim of this study was to investigate if apnea and other pathophysiological effects after BABT is a vagally mediated reflex. METHODS: Sixteen anesthetized pigs wearing body armor, of which five were vagotomized, were shot with a standard 7.62 mm assault rifle. These animals were compared with control animals (n = 8), shot with blank ammunition. We performed bilateral vagotomy before the shot and assessed the outcome on the apnea period, respiration, circulation, and brain function. Animals were monitored during a 2-hour period after the shot. RESULTS: Nonvagotomized animals had a mean apnea period of 22 (6-44) seconds. This group also showed a significant decrease in oxygen saturation compared with control animals. Furthermore, electroencephalogram-changes were more pronounced in nonvagotomized animals. In contrast, vagotomized animals were protected from apnea and showed only a minor decrease in oxygen saturation. All exposed animals showed impaired circulation, and postmortem examination revealed a pulmonary contusion. CONCLUSION: This study shows that apnea after BABT is a vagally mediated reflex that can be inhibited by bilateral vagotomy. Our results indicate that the initial apnea period is an important factor for hypoxia after BABT. Supported ventilation should begin immediately if the affected person is unconscious and suffers from apnea. It should continue until the neurologic paralysis disappears and sufficient spontaneous breathing begins.

Severe lung contusion and death after high-velocity behind-armor blunt trauma: relation to protection level.

The most-used safety recommendation for protective vests is that the impact should not cause more than a 44-mm impression in plasticine. The aim of this study was to investigate whether this criterion was sufficient if the vest was exposed to a high-velocity projectile. We tested the hypothesis with pigs divided into a 40-mm group (n = 10) and a 34-mm group (n = 8) protected by a vest allowing a 40-mm or 34-mm impression in plasticine, respectively. Five (50%) of 10 animals in the 40-mm group and 2 (25%) of 8 in the 34-mm group died due to the trauma. We observed severe lung hematoma, impaired circulation, desaturation, and electroencephalogram changes. These effects were more aggravated in the 40-mm group compared to the 34-mm group. Based on our results, the overall judgment is that the safety criterion of 44-mm impression is insufficient when a vest is exposed to a high-velocity projectile.

Local tissue reactions after nerve repair with ethyl-cyanoacrylate compared with epineural sutures.

Anastomosis of a nerve with cyanoacrylate following a lesion has previously been shown to indicate morphological and functional recovery to an extent comparable to that of conventional epineural sutures. In this study we examined the local tissue reactions after transection and repair of rat sciatic nerve, and compared sutures with a synthetic ethyl-cyanoacrylate adhesive. Many ED-1-immunoreactive macrophages were found accumulating on either side of the repair site whereas neurofilament labelling was less pronounced distal to the repair site seven days after reparation with cyanoacrylate compared with sutures. After six months, when reinnervation was completed, the difference in ED-1-immunoreactivity was still present but to a less extent. These results indicate that ethyl-cyanoacrylate seems to induce an increased inflammatory reaction, which may lead to accelerated Wallerian degeneration, and could therefore have benefits over conventional sutures for reconstruction of peripheral nerves.

Electroencephalogram, circulation, and lung function after high-velocity behind armor blunt trauma.

BACKGROUND: Behind armor blunt trauma (BABT) is defined as the nonpenetrating injury resulting from a ballistic impact on personal body armor. The protective vest may impede the projectile, but some of the kinetic energy is transferred to the body, causing internal injuries and occasionally death. The aim in this study was to investigate changes in electroencephalogram (EEG) and physiologic parameters after high-velocity BABT. METHODS: Eight anesthetized pigs, wearing body armor (including a ceramic plate) on the right side of their thorax, were shot with a 7.62-mm assault rifle (velocity approximately 800 m/s). The shots did not penetrate the armor and these animals were compared with control animals (n = 4), shot with blank ammunition. EEG and several physiologic parameters were thereafter monitored during a 2-hour period after the shot. RESULTS: All animals survived during the experimental period. Five of the exposed animals showed a temporary effect on EEG. Furthermore, exposed animals displayed decreased cardiac capacity and an impaired oxygenation of the blood. Postmortem examination revealed subcutaneous hematomas and crush injuries to the right lung. CONCLUSION: The results in our animal model indicate that high-velocity BABT induce circulatory and respiratory dysfunction, and in some cases even transient cerebral functional disturbances.

Long-term results of peripheral nerve repair: a comparison of nerve anastomosis with ethyl-cyanoacrylate and epineural sutures.

The morphological and functional recovery after repair of lesions to the sciatic nerve was studied in adult rats. We compared conventional microsuturing with a synthetic ethyl-cyanoacrylate adhesive. Six months after a unilateral lesion and subsequent repair the tibial branch to the lateral gastrocnemius muscle and the caudal sural cutaneous nerve were examined with electrophysiological measurements of motor and sensory conduction velocity, motor nerve action potentials, and quantitative histological examinations. There was functional reinnervation of motor and sensory nerves in both groups, as shown by equivalent recovery of motor and sensory conduction velocities, and motor nerve action potentials. Histological examination showed no significant difference in the mean diameter, fibre density or the number of regenerated myelinated motor and sensory axons distal to the repair site between the two groups. We conclude that anastomosis of the nerve with ethyl-cyanoacrylate adhesive supports morphological and functional recovery comparable to that of conventional epineural sutures after a unilateral lesion of the sciatic nerve in adult rats.